From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f68.google.com (mail-pl0-f68.google.com [209.85.160.68]) by mail.openembedded.org (Postfix) with ESMTP id 31041605C2 for ; Tue, 22 May 2018 10:33:41 +0000 (UTC) Received: by mail-pl0-f68.google.com with SMTP id bi12-v6so10634840plb.12 for ; Tue, 22 May 2018 03:33:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=+BfypqqcAMdRJR9E7csxNSLFqaQji6rc1PiAnW1VUJg=; b=rUb5+1C1hBZey/QQMkoJ8vDEz7ysrKZ4pE2bcuLUX0fTjNqXip07/7y2+flIHDUxgo sfHukuR6HAGUL9FrmtmZ3cFsYrcXTvXLnHeibIYkjxuynC947IYPIubSC85EI6swtgGx rOoI9GHDfjClrNFTtVNf/h57eUNMrAWxwAD+/Jjh8/kdAgKcI0mXlaXEgV8Mayu7E/B5 NDNTk2IfkKv8AU7rq8un+1AWWe1ZIoSclNST3GsscWKvqvNjid2tS9ZAGmP3/d6vxc29 1MCz+P0e2gXv6eyyS0Ijv6qLRnqJMxluFoALvf3wH7UXIJGwMoADb3kU+Me7tPsySaT2 SPPw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=+BfypqqcAMdRJR9E7csxNSLFqaQji6rc1PiAnW1VUJg=; b=jAf1vzExwAq2HNZ4ZFRYzLCdav1H4s+Rw//S3DHbfxXifNLrt88KBCCz4XeZzLCwR7 hEcXbAHJt31fZ45YezF62N3sEfvNvQ7c6qPlvvMZe6GPHNhOhwiSpkqzzaaLxw15BNGq cb4a0Tm/uoHh/7USwjBcOYSesd7wH35Giut2p/WT4RXZyPeADj4pD5Y5SQgVQNiROhcl Oc+XJpowzt0jUBuiqd9UH8Jn9y+t2AecKkqOJO6TFI57AFiyKp2yCCrPUMRmDuGROgFf drNr0W5CDr36yPcyCwtrsarn+m6XputjUwuKwx/FKA4VBvsXod49afY2gt7Hm+DviOf9 v1jA== X-Gm-Message-State: ALKqPwejPqCR1vFkyKvaJNtBicyK8EI8vvPLIE+qQw1kF6jc8vYF+IJZ Em9ftO4V0lJ+1UPw9kXsl5FSlwxNj1Ee7s02IeQ= X-Google-Smtp-Source: AB8JxZoU+cUtDS+VqHL90LjQ50rpX2eki//kW1Ghw/eFcHrj1gvCKu225xnrLvwhf5Ewx9j7PCJeq3oqSei18gZaDwE= X-Received: by 2002:a17:902:b78a:: with SMTP id e10-v6mr24497563pls.260.1526985222780; Tue, 22 May 2018 03:33:42 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a17:90a:8b91:0:0:0:0 with HTTP; Tue, 22 May 2018 03:33:12 -0700 (PDT) In-Reply-To: References: From: Khem Raj Date: Tue, 22 May 2018 06:33:12 -0400 Message-ID: To: Jef.Driesen@niko.eu Cc: Patches and discussions about the oe-core layer Subject: Re: [PATCH] arch-armv7a.inc: default to Thumb2 instruction set for armv7a and above X-BeenThere: openembedded-core@lists.openembedded.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Patches and discussions about the oe-core layer List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 May 2018 10:33:42 -0000 Content-Type: text/plain; charset="UTF-8" On Tue, May 22, 2018 at 5:58 AM, wrote: > Andre McCurdy wrote: >> Although there may still be specific cases which can benefit from the >> ARM instruction set, the Thumb2 instruction set is generally a better >> default for armv7a class CPUs. Distros such as Debian and Fedora have >> been targeting Thumb2 by default for some time. >> >> Note that setting ARM_INSTRUCTION_SET has no effect unless >> TUNE_FEATURES contains "thumb" (which is controlled by the "t" suffix >> in DEFAULTTUNE, e.g. armv7vehf-neon -vs- armv7vethf-neon, etc) so out >> of tree machine configs may need to update their DEFAULTTUNE to take >> advantage of this change. > > I recently ran into some major problems due to thumb vs arm. It turns out glibc doesn't support systems with thumb disabled anymore. See this bug report for details: > > https://sourceware.org/bugzilla/show_bug.cgi?id=23031 > > This might be useful input for this discussion also. > Thanks, this would be useful for us to check if kernel defconfig does not disable CONFIG_ARM_THUMB on armv6t2+ regardless of this patch. This patch however will require this option enabled too.